Method of making aluminum-containing zeolite with IFR structure

ABSTRACT

Zeolites having the IFR structure and containing aluminum in their crystal structure can be made by preparing a reaction mixture comprising a zeolite which is an active source of aluminum oxide, an active source of alkali metal oxide, an active source of an oxide of a tetravalent element, an organic template selected from the group consisting of a 1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cation and a N-benzyl quinuclidinium cation, and maintaining the reaction mixture under conditions sufficient to form crystals of the zeolite.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for preparingaluminum-containing crystalline zeolites having the IFR structure (“IFRzeolite”) using a zeolite as an active source of aluminum oxide.

2. State of the Art

IFR zeolites are known. U.S. Pat. No. 5,437,855, issued Aug. 1, 1995 toValyocsik, discloses a zeolite, designated “MCM-58”, having the IFRstructure prepared using a benzylquinuclidinium organic directing agent.However, it does not disclose the use of a zeolite as a source ofaluminum for MCM-58. U.S. Pat. No. 5,441,721, issued Aug. 15, 1995 toValyocsik, also discloses MCM-58, but prepared using a benzyltropaniumorganic directing agent. Use of a zeolite as the source of aluminum forMCM-58 is not disclosed. It has been discovered that when a zeolite(Na-Y) is used as the source of aluminum and benzyltropanium is used asthe structure directing agent, the only zeolite produced was FAU (astarting material). No zeolite with the IFR structure was made (seeComparative Example B below). Both patents are incorporated by referenceherein in their entirety. U.S. Pat. No. 5,653,956, issued Aug. 5, 1997to Zones, discloses a zeolite, designated SSZ-42, prepared using anorganic templating agent selected from the group consisting of1-benzyl-4-aza-1-azonia-bicyclo [2.2.2] octane cations andN-benzyl-1-azabicyclo[2.2.2]octane cations. The SSZ-42 may containoxides of boron, aluminum, gallium, iron or titanium, but at least 50%of those oxides must be boron oxide. Zeolites are disclosed as apossible source of aluminum or boron (see col. 8). In Example 14, analuminum-containing SSZ-42 is made, but the aluminum is added to theSSZ-42 by post-treatment after the boron-containing SSZ-42 was prepared.Likewise, in Example 16 a boron- and gallium-containing SSZ-42 is madeby adding gallium by post-treatment of previously made SSZ-42. InExample 20, an aluminum- and boron-containing (50/50) SSZ-42 is prepareddirectly using sodium borate as the source of boron and sodium aluminumtrihydrate as the source of aluminum. U.S. Pat. No. 5,653,956 isincorporated herein by reference in its entirety.

U.S. Pat. No. 5,340,563, issued Aug. 23, 1994 to Zones et al., disclosesan improved method for preparing large pore zeolites. The methodinvolves preparing a reaction mixture containing a source zeolite, analkali metal, nitrogen containing organic cation, a source of silica andwater. The source zeolite contains sodalite substructures and has atetrahedra atom density of less than about 15 TO₂ per 1000 Angstroms³.Examples of zeolites prepared by this method are SSZ-25, SSZ-31, SSZ-37,beta and ZSM-12. Zeolites A, N-A, ZK-4, faujasite, X, Y, ZK-5 and rhoare disclosed as source zeolites. U.S. Pat. No. 5,340,563 isincorporated by reference herein in its entirety.

U.S. Pat. No. 4,503,024, issued Mar. 5, 1985 to Bourgogne et al.,discloses synthesizing zeolites using zeolites as reactants. It doesnot, however, disclose the synthesis of a zeolite having the IFRstructure.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided a method forpreparing a zeolite having the IFR structure comprising:

(a) preparing a reaction mixture comprising (1) a zeolite which is anactive source of aluminum oxide, (2) an active source of alkali metaloxide, (3) an active source of an oxide of a tetravalent element, and(4) an organic template selected from the group consisting of aN-benzyl-1,4-diazabicyclo[2.2.2] octane cation and a N-benzylquinuclidinium cation, wherein said reaction mixture has a compositionin terms of mole ratios of oxides falling within the following ranges:

YO₂/Al₂O₃ about 5 to about 100

OH⁻/YO₂ about 0.05 to about 0.50

Q/YO₂ about 0.10 to about 1.0

M_(2/n)/YO₂ about 0.005 to about 0.50

H₂O/YO₂ about 3 to about 100

Q/Q+M_(2/n) about 0.50 to about 0.95

wherein Y is silicon, germanium or mixtures thereof, Q is an1-benzyl-4-aza-1-azonia bicyclo[2.2.2]octane cation or N-benzylquinuclidinium cation, M is an alkali metal cation or alkaline earthmetal cation and n is the valence of M; and (b) maintaining the reactionmixture under conditions sufficient to form crystals of the IFR zeolite.

Also provided in accordance with the present invention is an essentiallyboron-free zeolite having a composition, as synthesized and in theanhydrous state, in terms of mole ratios as follows:

YO₂/Al₂O₃ about 5 to about 100

OH³¹/YO₂ about 0.05 to about 0.50

Z/YO₂ about 0.10 to about 1.0

M_(2/n)/YO₂ about 0.005 to about 0.50

H₂O/YO₂ about 3 to about 100

Z/Z+M_(2/n) about 0.50 to about 0.95

wherein Y, M and n are as defined above and Z is a1-benzyl-4-aza-1-azonia bicyclo[2.2.2]octane cation.

Further provided in accordance with the present invention is a zeolitehaving the IFR crystal structure and having a composition, assynthesized and in the anhydrous state, in terms of mole ratios asfollows:

YO₂/Al₂O₃ about 5 to about 100

YO₂/B₂O₃ about 5 to about 100

OH⁻/YO₂ about 0.05 to about 0.50

Z/YO₂ about 0.10 to about 1.0

M_(2/n)/YO₂ about 0.005 to about 0.50

H₂O/YO₂ about 3 to about 100

Z/Z+M_(2/n) about 0.50 to about 0.95

wherein Y, M, and n are as defined above and Z is a1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cation and wherein theamount of aluminum is greater than the amount of boron.

DETAILED DESCRIPTION OF THE INVENTION

Zeolites having the IFR structure are those which, after calcination,have a crystalline structure whose X-ray powder diffraction patternincludes the characteristic lines shown in Table I below:

TABLE I CALCINED IFR ZEOLITE 2 Theta d/n Relative Intensity^((a)) 8.2210.75 VS 9.76 9.06 W 16.42 5.394 W 19.22 4.615 W 20.48 4.333 M 20.844.259 M 21.48 4.134 W 21.72 4.088 W-M 23.68 3.754 W 24.06 3.696 W 24.943.568 W 25.40 3.504 W 26.60 3.348 M 29.56 3.019 W ^((a))The X-raypattern is based on a relative intensity scale in which the strongestline in the X-ray pattern is assigned a value of 100: W (weak) is lessthan 20; M (medium) is between 20 and 40; S (strong) is between 40 and60; and VS (very strong) is greater than 60.

The variation in the scattering angle (two theta) measurements, due toinstrument error and to differences between individual samples, isestimated at +/− 0.20 degrees.

The IFR zeolites prepared in accordance with this invention willtypically have a silica to alumina mole ratio of about 20 to about 80.

IFR zeolites can be prepared from an aqueous solution comprising sourcesof an alkali metal oxide, the templating agent, an active source(s) ofdesired tetravalent element oxide(s), and an active source(s) ofaluminum oxide. The reaction mixture should have a composition, in termsof mole ratios, within the ranges shown in Table A.

TABLE A IFR ZEOLITE REACTION MIXTURE Broad Preferred YO₂/Al₂O3 5 andgreater 15 and greater (to about 100) (to about 100) OH⁻/YO₂ 0.05 to0.50 0.15 to 0.30 Q/YO₂ 0.10 to 1.0 0.10 to 0.25 M_(2/N)/YO₂ 0.005 to0.50 0.03 to 0.10 H₂O/YO₂ 3 to 100 20 to 50 Q/Q + M_(2/n) 0.50 to 0.950.66 to 0.90

wherein Y is selected from the group consisting of silicon, germanium,and mixtures thereof, Q is comprised of1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cations or N-benzylquinuclidinium cations, M is an alkali metal cation or alkaline earthmetal cation and n is the valence of M.

In practice, aluminum-containing IFR zeolites are prepared by a processcomprising:

(a) preparing an aqueous solution containing sources of the oxideslisted in Table A above, wherein the source of aluminum is analuminum-containing zeolite, and a1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cation or benzyltropaniumcation templating agent having an anionic counterion which is notdetrimental to the formation of the IFR zeolite;

(b) maintaining the aqueous solution under conditions sufficient to formcrystals of IFR zeolite; and

(c) recovering the crystals of the IFR zeolite.

The 1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cation templating agenthas the following general formula:

The anion (X⁻) associated with the cation may be any anion which is notdetrimental to the formation of the zeolite. Representative anionsinclude halide, e.g., fluoride, chloride, bromide and iodide, hydroxide,acetate, sulfate, tetrafluoroborate, carboxylate, and the like.Hydroxide is the most preferred anion.

The N-benzyl-1,4-diazabicyclo[2.2.2]octane cation (“benzyl DABCO”)templating agent has the advantage that it is less expensive than thebenzylquinuclidinium organic directing agent of U.S. Pat. No. 5,437,855and the benzyltropanium organic directing agent of U.S. Pat. No.5,441,721. However, it has been found that aluminosilicate IFR zeolitescan not be made directly using conventional sources of alumina, such assodium aluminate (see Comparative Example A below) when benzyl DABCO isused as the templating agent. Rather, when benzyl DABCO is used withsuch a conventional source of alumina, a different zeolite results.Instead, a borosilicate IFR zeolite has to be prepared first, followedby exchange of the boron for aluminum. By using the source zeolites ofthis invention, aluminosilicate IFR zeolites can be directly preparedusing benzyl DABCO as the templating agent, resulting in significantcost savings.

The N-benzyl quinuclidinium cation templating agent has the followingformula:

where X⁻ is as defined above.

The reaction mixture used to prepare the IFR zeolites may also containan active source of boron oxide, such as boric acid. When the boronsource is present it is generally used in a YO₂/B₂O₃ mole ratio of about5 to about 100, preferably from about 20 to about 100, where YO₂ isdefined above.

Typical sources of silicon oxide include silicates, silica hydrogel,silicic acid, fumed silica, colloidal silica, tetra-alkylorthosilicates, and silica hydroxides.

A zeolite reagent provides the source of aluminum for the IFR zeolite.In some cases, the source zeolite may provide a source of silica. Use ofa source zeolite reagent as a source of alumina is described inaforementioned U.S. Pat. No. 5,340,563.

The term “source zeolite” as used herein means an aluminosilicatezeolite used as a reactant in a reaction mixture to produce a zeolitehaving the IFR structure. The source zeolite used in accordance withthis invention contains sodalite substructures and has a tetrahedra atomdensity of less than about 15 TO₂/1000 Angstroms³ (TO₂ representing thetetrahedral oxides in the crystal structure). Preferably, the sourcezeolite is zeolite A, N-A, ZK-4, faujasite, X, Y, ZK-5 or rho. Thesilica to alumina mole ratio in these source zeolite should be fromabout 2 to about 20. Preferably, the silica to alumina mole ratio inthese source zeolites should be from about 2 to about 10, and mostpreferably from about 2 to about 5.

The term “sodalite substructures” as used herein means a truncatedoctahedron having 36 edges, 24 vertices, six square faces, and eighthexagonal faces with a tetrahedral atom located at each vertex. Oxygenatoms are located between the tetrahedral atoms, but not necessarily onthe edge.

Tetrahedra atom densities for various zeolitic structures is given inmore detail in “Zeolite Molecular Sieves” by D. W. Breck (1984), thedisclosure of which is incorporated by reference herein.

The use of source zeolites having sodalite structures and which have atetrahedra atom density of less than about 15 TO₂/1000 Angstroms³ allowsa relatively smaller concentration of the organic template to be presentin the reaction mixture. Because one can use lower amounts of thetemplate, and because the source zeolite can be used in the ammoniumform as well as the alkali metal form, preferably as the sodium form ormixtures of ammonium and sodium forms, lower cost zeolites may beobtained.

Zeolite A and the conventional preparation thereof is described in U.S.Pat. No. 2,882,243. Zeolite N-A and the conventional preparation thereofis described in U.S. Pat. No. 3,306,922. Zeolite ZK-4 and theconventional preparation thereof is described in U.S. Pat. No.3,247,195. Zeolite X and the conventional preparation thereof isdescribed in U.S. Pat. No. 2,882,244. Zeolite Y and the conventionalpreparation thereof is described in U.S. Pat. No. 3,130,007. ZeoliteZK-5 and the conventional preparation thereof is described in U.S. Pat.No. 3,247,195. Zeolite rho and the conventional preparation thereof isdescribed in U.S. Pat. No. 3,904,738. The disclosures of these patentsare incorporated by reference herein in their entirety.

Typically, an alkali metal hydroxide, such as the hydroxide of sodium,potassium, lithium, or cesium is used in the reaction mixture; however,this component can be omitted so long as the equivalent basicity ismaintained. The templating agent may be used to provide hydroxide ion.Thus, it may be beneficial to ion exchange, for example, a hydroxideanion for a halide ion in the templating agent, thereby reducing oreliminating the alkali metal hydroxide quantity required. The alkalimetal cation may be part of the as-synthesized crystalline oxidematerial, in order to balance valence electron charges therein.

The reaction mixture is maintained at an elevated temperature until thecrystals of the zeolite are formed. This hydrothermal crystallization isusually conducted under autogenous pressure, at a temperature between100° C. (212° F.) and 200° C. (392° F.), preferably between 135° C.(275° F.) and 180° C. (356° F.). The crystallization period is typicallygreater than 1 day and preferably from about 3 days to about 7 days. Thezeolite can be prepared with or without mild stirring or agitation.

During the hydrothermal crystallization step, the IFR zeolite crystalscan be allowed to nucleate spontaneously from the reaction mixture.However, the use of IFR zeolite crystals as seed material can beadvantageous in decreasing the time necessary for completecrystallization to occur. In addition, seeding can lead to an increasedpurity of the product obtained by promoting the nucleation and/orformation of IFR zeolite over any undesired phases. When used as seeds,IFR zeolite crystals are added in an amount sufficient to direct and/oraccelerate crystallization, i.e., typically between about 0.1 and about10% of the weight of silica used in the reaction mixture.

Once the zeolite crystals have formed, the solid product is separatedfrom the reaction mixture by standard mechanical separation techniquessuch as filtration. The crystals are water-washed and then dried, e.g.,at 90° C. (194° F.) to 150° C. (302° F.) for from 8 to 24 hours, toobtain the as-synthesized, IFR zeolite crystals. The drying step can beperformed at atmospheric pressure or under vacuum.

Aluminum-containing IFR zeolites are useful in hydrocarbon conversionreactions. Hydrocarbon conversion reactions are chemical and catalyticprocesses in which carbon containing compounds are changed to differentcarbon containing compounds. Examples of hydrocarbon conversionreactions in which these zeolites are expected to be useful includecatalytic cracking, hydrocracking, dewaxing, alkylation, and olefin andaromatics formation reactions.

A primary advantage of the present invention is that aluminum-containingIFR zeolites can be made directly, i.e., there is no need to firstprepare a boron-containing IFR zeolite and then substitute aluminum forthe boron in the zeolite. Thus, the present invention providesas-synthesized, aluminum-containing, essentially boron-free IFR zeolitesthat contain the N-benzyl-1,4-diazabicyclo[2.2.2] octane cation organictemplate. As used in this context, the term “essentially boron-free”means that the as-synthesized zeolite contains less than about 500 ppm.

The present invention also provides a zeolite having the IFR crystalstructure in the as-synthesized state (i.e., prior to removal of theorganic template from the zeolite) that contains both aluminum andboron. In this case, the amount of aluminum contained in the crystalstructure is greater than the amount of boron contained in the crystalstructure. In other words, of the combined amount of aluminum and boronin the crystal structure, less than 50%, preferably less than 30%, isboron.

EXAMPLES

The following examples demonstrate but do not limit the presentinvention.

Example 1 Synthesis of 1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octaneCation

145 Grams of 1,4-diazabicyclo[2.2.2]octane (commonly referred to as“DABCO”) is dissolved in 2.5 liters of ethyl acetate and chilled to 0°C. (32° F.). 209 Grams of benzyl bromide is added dropwise while thechilled solution is stirred. Caution should be exercised because thereaction is rapid and requires cooling. The product is collected byfiltration and recrystallized from a minimum of warm methanol. Therecrystallized product gives a microanalysis and NMR pattern consistentwith the 1:1 adduct. The quaternary ammonium compound is ion exchangedusing hydroxide exchange resin AG 1-X8 from BioRad. The exchangedsolution is titrated for molarity and the yield of exchange is greaterthan 90%. The resulting compound is designated Template A.

Example 2 Synthesis of IFR Zeolite

2.0 Millimoles of Template A is combined with 2.0 millimoles of NaOH in8 cc water. 0.28 Grams of Y zeolite (LZY-52 from Union CarbideCorporation, SiO₂/Al₂O₃ mole ratio near 5) is added in as well as 0.72grams of CAB-O-SIL M-5, a fumed silica. The reaction mixture is heatedin the Teflon cup of a 23 ml volume Parr digestion bomb, rotating on aspit at 43 RPM while being heated to 160° C. The reaction is heated for6 days under these conditions and then cooled. The pH having risenwithin the reactor to greater than 12, it is deemed that organozeoliteproduct has formed. The product is collected by filtration, givensubsequent washing and drying and then analyzed by X-ray diffraction.The product is an IFR zeolite with an X-ray pattern consistent withTable I above. The product contains a SiO₂/Al₂O₃ mole ratio (SAR) of 35as determined by wet chemical methods.

Examples 3-17 Synthesis of IFR Zeolite

In the following examples the SAR is varied in the runs by using theconditions of Example 2, and either increasing or decreasing thequantity of CAB-O-SIL. The conditions and XRD data results are given inTable B.

TABLE B VARIATION IN SAR EX. NO. REACTANT SAR XRD PRODUCT(S) 3 20 IFRzeolite and some unreacted LZY-52 4 24 IFR zeolite and some LZY-52 5 28IFR zeolite and a little remaining LZY52 6 32 IFR zeolite 7 36 (Ex. 2)IFR zeolite 8 40 IFR zeolite 9 44 IFR zeolite 10 47 IFR zeolite 11 50IFR zeolite 12 60 IFR zeolite 13 64 IFR zeolite 14 72 IFR zeolite 15 80IFR zeolite and a trace of ZSM- 12 16 90 IFR zeolite and a trace ofZSM-12 17 100 ZSM-12 and LZY-52

Examples 18-20 Synthesis of Aluminoborosilicate IFR Zeolite

In the following reactions, the procedure is used as in Example 2 exceptvariable amounts of boron, as sodium borate, are added to provide an IFRzeolite product containing both boron and aluminum substituted into thelattice. Table C below shows the ratios of boron and aluminum and thecorresponding zeolite product(s).

TABLE C Ex. No. Al/ B ratio in reaction Product(s) 18 1 (50/50) IFRzeolite & trace of beta 19 2 (66/33) IFR zeolite & trace of beta 20 4(80/20) IFR zeolite & a little LZY-52

Example 21 Micropore Volume

One of the advantages of this synthetic method is the production of anactive aluminosilicate or aluminoborosilicate zeolite material with ahigh micropore volume, conducive to higher catalytic activity. Theproduct of Example 2 is calcined to 1100° F. (593° C.), in stages andunder a stream of nitrogen with a very small air bleed. The stages to125° C. (257° F.) at 50° C. (122° F.)/hr, hold for two hours, 50° C.(122° F.)/hr to 540° C. (1004° F.), hold for four hours, 50° C. (122°F.)/hr to 593° C. (1100° F.) with a final hold for four hours. Thecalcined material is then ion-exchanged twice with ammonium nitrate,followed by a washing and drying step. The micropore volume, determinedby use of nitrogen as adsorbate, is found to be 0.20 cc/gm. This valuematches that found for the calcined IFR borosilicate zeolite SSZ-42 (seeExample 12 in U.S. Pat. No. 5,653,956), and is in good agreement withthe value expected from the structure determination for SSZ-42 (Chen etal., J. Chem. Soc. Chem. Comm., pg. 1775, 1997). This demonstrates thatthere is no pore blockage for this product.

Example 22 Constraint Index

The utility of the product material can be seen by subjecting theproduct of Example 21 to a catalytic cracking experiment using theConstraint Index determination. 0.50 Gram of 20-40 mesh granules (afterpelletization to 3000 psi and pellet breakup) of the product of Example21 is packed into a ¼ inch stainless steel reactor tube with alundum onboth sides of the zeolite bed. The reactor is placed in a Lindburgfurnace and heated to 540° C. (1004° F.) for drying. At 125° C. (257°F.) helium is introduced into the reactor at 10 cc/minute andatmospheric pressure. The temperature is gradually raised to 288° C.(550° F.) over 40 minutes. Feed is introduced by means of a syringe pumpat a rate of 0.62 cc/hr of a 50/50 (v/v) mixture of n-hexane and3-methylpentane. Direct sampling onto a gas chromatograph is begun atten minutes.

This material gives a C.I. conversion of 93% at 10 minutes on-stream ata low temperature of 550° F. (288° C.). This activity compares favorablywith the activity of the very strong acid zeolite catalysts, beta andSSZ-26.

Example 23 Larger Scale Synthesis of IFR Zeolite

605 Milliliters of 0.93M aqueous solution of Template A (562 mmol ofTemplate A), 375 ml of 1.0 N aqueous solution of NaOH (375 mmol ofNaOH), 1000 ml of water (total water=102.23 mmol), 201 grams ofCAB-O-SIL M-5 silica (3.283 moles silica) and 64.5 grams LZY-52 zeolite(0.5 mole silica, 0.218 mole Al, 0.218 mole Na, 0.9 mole water) are allmixed in a 1-gallon steel liner (the reagents are listed in order ofmixing). To the resulting gel, small amounts (on the order of 1.5 or 3weight percent based on the weight of the silica) of aluminum-containingIFR zeolite crystals are added as seeds. The gel is then heated in anautoclave at 160° C. at 100 rpm for 120 hours. When 1.5 wt. % of seedsis used, the resulting product contains IFR zeolite as the majorcrystallization product, with beta zeolite as a minor impurity and atrace amount of MOR. When 3 wt. % seeds is used, IFR zeolite is obtainedwith only a trace amount of MOR.

Example 24 Synthesis of IFR Zeolite Using Na-X Zeolite

2.42 ml of 0.93 M solution of benzyl DABCO hydroxide (2.25 mmol ofbenzyl DABCO), 1.5 gm of 1.0 N sodium hydroxide solution and enoughde-ionized water to reach a total weight of 7.4 gm are added to a 23 ccTeflon liner. To the resulting mixture is added 0.175 gm of Na-X zeolite(Al/Si=1), and 0.86 gm of CAB-O-SIL M-5 silica. The resulting gel isplaced in a steel reactor and heated at 160° C. while being tumbled at43 rpm. After heating and tumbling for six days, the reaction iscomplete. The resulting mixture (a solution with settled fine solids) isfiltered and the solids are washed with deionized water several times,and then air dried overnight. The reaction yields 0.95 gm of a zeolitehaving the IFR structure, with a small amount of Gismondine (P zeolite)impurity, as indicated by X-ray diffraction analysis.

Example 25 Synthesis of IFR Zeolite Using Na-A Zeolite

2.42 ml of 0.93 M solution of benzyl DABCO hydroxide (2.25 mmol ofbenzyl DABCO), 1.5 gm of 1.0 N sodium hydroxide solution and enoughde-ionized water to reach a total weight of 7.4 gm are added to a 23 ccTeflon liner. To the resulting mixture is added 0.175 gm of Na-A zeolite(Al/Si=1), and 0.86 gm of CAB-O-SIL M-5 silica. The resulting gel isplaced in a steel reactor and heated at 160° C. while being tumbled at43 rpm. After heating and tumbling for six days, the reaction iscomplete. The resulting mixture (a solution with settled fine solids) isfiltered and the solids are washed with deionized water several times,and then air dried overnight. The reaction yields 1.0 gm of a zeolitehaving the IFR structure, with a trace amount of Gismondine (P zeolite)impurity, as indicated by X-ray diffraction analysis.

Example 26 Synthesis of IFR Zeolite Using N-Benzyl Quinuclidinium Cation

In a 23 cc. Teflon liner is placed 4.75 ml. of 0.475M solution ofN-benzyl quinuclidinium hydroxide (2.25 mmol. N-benzyl quinuclidiniumhydroxide), 1.5 g. of 1N sodium hydroxide. Water is added until a totalweight of 7.36 g. is reached. To the resulting solution is added 0.26 g.of LZY-52 zeolite, and 0.81 g. of CAB-O-SIL M-5 fumed silica. Theresulting gel is sealed in the Teflon liner and placed in a steel Parrreactor and heated in an oven at 160° C. while rotating at 43 rpm. Thereaction is monitored by following the change in the pH of the reactionmixture and by Scanning Electron Microscopy. The reaction requires 12days to complete. The reaction mixture is then filtered and the obtainedsolid material is washed several times with deionized water andair-dried over night. The reaction yields 1.1 g. of a mixture of an IFRzeolite and a FAU zeolite (the starting reagent), as determined by X-raydiffraction analysis.

Comparative Example A Use of Benzyl DABCO and Sodium Aluminate

2.42 Ml of 0.93 M solution of benzyl DABCO hydroxide (2.25 mmol ofbenzyl DABCO), 1.5 gm of 1.0 N sodium hydroxide solution and enoughde-ionized water to reach a total weight of 7.38 gm are added to a 23 ccTeflon liner. To the resulting mixture is added 0.0734 gm of sodiumaluminate (containing 17.27% water by weight), and 0.91 gm of CAB-O-SILM-5 silica. The resulting gel is placed in a steel reactor and heated at160° C. while being tumbled at 43 rpm. After heating and tumbling for 12days, the reaction is complete. The resulting mixture (a solution withsettled solids) is filtered and the solids are washed with deionizedwater several times, and then air dried overnight. The reaction yields1.1 gm of a beta zeolite, as indicated by X-ray diffraction analysis. Nozeolite having the IFR structure is observed.

Comparative Example B Use of Benzyl Tropanium Cation

In a 23 cc. Teflon liner is placed 4 ml. of 0.57M solution of N-benzyltropanium hydroxide (2.25 mmol. N-benzyltropanium hydroxide), 1.5 g. of1N sodium hydroxide. Water is added until a total weight of 7.4 g. isreached. To the resulting solution is added 0.26 g. of LZY-52 zeoliteand 0.81 g. of CAB-O-SIL M-5 fumed silica is added. The resulting gel issealed in the Teflon liner and placed in a steel Parr reactor and heatedin an oven at 160° C. while rotating at 43 rpm. The reaction ismonitored by following the change in the pH of the reaction mixture andby Scanning Electron Microscopy. After heating for 24 days the reactionmixture is filtered and the obtained solid material is washed severaltimes with deionized water and air-dried over night. The reaction yields1.0 g. of amorphous material, FAU zeolite (starting reagent), and atrace of layered material, as determined by X-ray diffraction analysis.No IFR zeolite is observed.

Comparative Example C Use of N-Benzyl Tropanium Cation and Sodium Borate

In a 23 cc. Teflon liner is placed 5.25 ml. of 0.57M solution ofN-benzyl tropanium hydroxide (3 mmol. N-benzyl tropanium hydroxide), 1.2g. of 1N sodium hydroxide. Water is added until a total weight of 12 g.is reached. To the resulting mixture is added 0.06 g. of sodium boratedecahydrate, and the mixture is stirred until the sodium boratedissolves. Finally, 0.9 g. of CAB-O-SIL M-5 fumed silica is added. Theresulting gel is sealed in the Teflon liner and placed in a steel Parrreactor and heated in an oven at 160° C. while rotating at 43 rpm. Thereaction is monitored by following the change in the pH of the reactionmixture and by Scanning Electron Microscopy. The reaction requires 18days to complete. The reaction mixture is then filtered and the obtainedsolid material is washed several times with deionized water andair-dried over night. The reaction yields 0.8 g. of a boron-containingIFR zeolite and a trace amount of layered material, as determined byX-ray diffraction analysis.

Comparative Example D Use of Aluminum Sulfate as the Aluminum Source

In a 23 cc Teflon liner is placed 5.22 ml of 0.93M solution of benzylDABCO-OH (4.85 mmol of benzyl DABCO), and 1.5 gm of 1.0N sodiumhydroxide solution. De-ionized water is added until the total weightreaches 7.36 gm. To this mixture, 0.293 GM of aluminum sulfateoctadecahydrate (Al₂(SO₄)₃ 18H₂O) and 0.91 gm of CAB-O-SIL-M-5 areadded. The resulting gel is placed in a steel reactor and heated at 160°C. and tumbling at 43 rpm. After heating and tumbling for 12 days, thereaction is complete. The resulting mixture (a solution with settledsolids) is filtered and the solids are washed with de-ionized waterseveral times and then dried in an oven at 120° C. for 30 minutes. Thereaction yields 1 gm of BETA zeolite as indicated by XRD analysis. NoIFR zeolite is observed. (Organic/Si=0.32; Al/Si=0.059; Na/Si=0.15;OH/Si=0.25: H₂O/Si=27). In this reaction protons are generated due tothe use of aluminum sulfate as an aluminum source. The amount ofhydroxide takes into account hydroxide lost from balancing the protonsfrom the aluminum sulfate. To account for the consumed hydroxide by thegenerated protons and to keep the OH/Si ratio in the desired range, moreof the organic template is added as the hydroxide source. In comparison,when the extra hydroxide is added in the form of NaOH, the reactionmixture remains as a gel after heating for five weeks.

What is claimed is:
 1. A method for preparing a zeolite having the IFRstructure comprising: (a) preparing a reaction mixture comprising (1) azeolite which is an active source of aluminum oxide, (2) an activesource of alkali metal oxide, (3) an active source of an oxide of atetravalent element, and (4) an organic template selected from the groupconsisting of a 1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cation anda N-benzyl quinuclidinium cation, wherein said reaction mixture has acomposition in terms of mole ratios of oxides falling within thefollowing ranges: YO₂/Al₂O₃ about 5 to about 100 OH⁻/YO₂ about 0.05 toabout 0.50 Q/YO₂ about 0.10 to about 1.0 M_(2/n)/YO₂ about 0.005 toabout 0.50 H₂O/YO₂ about 3 to about 100 Q/Q+M_(2/n) about 0.50 to about0.95 wherein Y is silicon, germanium or mixtures thereof, Q is an1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cation or N-benzylquinuclidinium cation, M is an alkali metal cation or alkaline earthmetal cation and n is the valence of M; and (b) maintaining the reactionmixture under conditions sufficient to form crystals of the IFR zeolite.2. The method of claim 1 wherein the reaction mixture has the followingcomposition: YO₂/Al₂O₃ about 15 to about 100 OH−/YO₂ about 0.15 to about0.30 Q/YO₂ about 0.10 to about 0.25 M_(2/n)/YO₂ about 0.03 to about 0.10H₂O/YO₂ about 20 to about 50 Q/Q+M_(2/n) about 0.66 to about 0.90. 3.The method of claim 1 wherein the reaction mixture further comprises anactive source of boron oxide in a mole ratio of oxides of about 5 toabout 100 YO₂/B₂O₃ and the amount of boron is less than the amount ofaluminum.
 4. The method of claim 2 wherein the reaction mixture furthercomprises an active source of boron oxide in a mole ratio of oxides ofabout 5 to about 100 YO₂/B₂O₃ and the amount of boron is less than theamount of aluminum.
 5. The method of claim 1 wherein the active sourceof aluminum oxide is a zeolite that contains sodalite substructures andhas a tetrahedra atom density of less than about 15 TO₂/1000 Angstroms³.6. The method of claim 1 wherein the active source of aluminum oxide isY zeolite in the sodium form.
 7. The method of claim 1 wherein theactive source of aluminum oxide is zeolite A in the sodium form.
 8. Themethod of claim 1 wherein the active source of aluminum oxide is zeoliteN-A in the sodium form.
 9. The method of claim 1 wherein the activesource of aluminum oxide is zeolite ZK-4 in the sodium form.
 10. Themethod of claim 1 wherein the active source of aluminum oxide isfaujasite in the sodium form.
 11. The method of claim 1 wherein theactive source of aluminum oxide is zeolite X in the sodium form.
 12. Themethod of claim 1 wherein the active source of aluminum oxide is zeoliteZK-5 in the sodium form.
 13. The method of claim 1 wherein the activesource of aluminum oxide is zeolite rho in the sodium form.
 14. Themethod of claim 1 wherein the organic template comprises an1-benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane cation.
 15. The method ofclaim 1 wherein the organic template comprises anN-benzyl-quinuclidinium cation.